How can I solve part b of exercise 3.6 from the book "Artificial Intelligence: A Modern Approach"?
Initial state: initial position of the monkey.
Possible actions


climb on the crate, 
get down the crate, 
move the crate from one spot to another, 
stack one crate on another, 
walk from one spot to another,
grab bananas (if standing on the crate)

Goal test: did the monkey get the bananas?
Cost function: the number of actions completed